lntroduction to Soils in Permaculture Designers Manual

Permaculture Designers Manual

 

CHAPTER 8 – WATER IN PERMACULTURE

Section 8.1 –

lntroduction to Soils in Permaculture Designers Manual

 

 

The best fertilizer is the footsteps of the gardener

(Chinese Proverb)

 

The properties and treatments of common soil types in specific climatic areas are summarized in later units, so that in this Module we deal more with soil as a material, including some of the ways to stabilize and assist soils in retaining their productivity (soil conservation and soil conditioning).

Soils defy precise treatment, as their structure (and permeability), organic content, gaseous components (some derived from the atmosphere, some from pro­cesses within the soil, and some exhaled from the sediments below), minerals, pH, and water (or rather solute status) changes from hour to hour with soil depth and treatment, and in response to micro elevations.

Added to this is the fact that many soils are originally complex mixtures derived from a variety of rock types and that they may have had a very long and varied history.

 

A final factor is that despite all our knowledge, in spite of soil services and soil analysis, and despite the best attempts of people to care for land, we are losing topsoil at an ever-increasing rate.

Australia, where I live and write, has perhaps of its original soils in fair condition. The rest are washed or blown away, or sadly depleted in structure and yield; this is true of most countries of the world where extractive agriculture and forestry occurs.

 

The closer soils are defined, it seems, the less likely we are to know them, notwithstanding this specific uncertainty, there are some sustainable approaches to soil maintenance and to soil rehabilitation.

This is in these areas that we will outline strategies. Keep in mind, however, that we are always dealing with a matrix or mosaic that is in constant variation in place and time.

Nobody can be dogmatic about any natural system. Soil science concentrates very much on what is their (classifications), but not on how to evolve soil.

Often it is left to amateurs-gardeners and farmer to create good soil by water control, modest aeration, and plant and animal management.

Farmers and gardeners seem to be so often the practical, innovative, experimental, successful group (while often ignored by academics) that I despair of esoteric knowledge ever preceding effective action.

 

Very  few  farmers can persuade a group of scientists to assess their apparently successful soil trials. It Is past time that we assessed whether more “science” is not being done by outdoor people than by scientists who (like myself) more often collect the results of others than generate them by example.

Science is good at explaining why things work, and thus making skills teachable.

It is not so good at initiating field work, or in training people already in the field to work effectively.

It is hard to say if scientists lack the means to get into the real work, or if they choose science to escape from field problems. It is hard out in the field of erosion, landlords, foreclosures, poverty, greed, malnutrition, and exploitation, but that’s where all the action is.

 

A field   approach   means choosing values,  getting Involved  with people, and inspiring broad scale change.

Farmers’ field  days advance knowledge far more effectively than scientific papers, and local educational sessions more than either of these.

However both scientists and farmers have much to “give and take“. This sort of coalition is slowly starting to happen as a result of joint concern on a private level.

Soils can be RESIDUAL (resting in place over their present rock) or TRANSPORTED by water, ice, gravity, and wind.

In their formation the key factors are rock type, climate, and topography (or land form).

 

Water has a key role in rock breakdown, combining with such common minerals as feldspars in rock to swell and fracture the rock, then to hydrate the feldspars to kaolin, clay, and potassium carbonate.

The carbonates released make of soil water a stronger carbonic add than it is as rain.

Atmospheric oxygen dissolves in rain to oxidize iron minerals pyrites) and forms both haematite and a quantity of sulphuric acid, which again dissolves metals, so that water makes an effective rock decomposer, even without invoking the expansion of water as ice, or the power of ice (as glaciers) to grind rocks to flour.

Plants too are wedging open rocks and mineral particles, recreating acids, and transporting minerals in their sap to other locations.

All of this work creates a mantle of topsoil, which is estimated to build at about 2-4 t/ha per year as un-compacted topsoil, but which we remove at a rate of from 40-500 t/year in cropping and soil tillage.

Even the most ideal tillage just keeps pace with the most ideal conditions of soil formation, and in the worst cases we can remove 2000 years of soil in a single erosion season, or one sequence of flood or strong wind over cultivated soils.

 

The only places where soils are conserved or increased are:

In uncut forests;

Under the quiet water of lakes and ponds;

In prairies and meadows of permanent plants; and

Where we grow plants with mulched or non­tillage systems.

 

These then are the core subjects of sustainable societies of any conceivable future.

They are not, you might notice, the subjects most taught in the agricultural colleges or forestry courses of the recent past, nor do they occupy the minds of politicians, investment bankers, or TV stars.

Before starting on the complex subject of soils (and I am not a soil scientist), it is wise to draw back a little and consider the question of soils from some very different viewpoints, or sets of values.

 

They are broadly these:

Health (both human and plant).

We must be careful and conservative in approach, especially in the area of biocides and high levels of artificial fertilizers. After all, our ancestors lived to a ripe old age on home-grown produce without the benefit of herbicides, pesticides, or artificial fertilizers.

We must therefore improve on, not lessen, that factor of long-tested vitality that was, and is, integral to good gardeners.

 

Not that I believe that their health was purely due to diet. Several other factors associated with gardening maybe one day better assessed, including:

Mild but regular exercise: gardening is a sort of steady and non-stressing tai chi.

Meditation: we can sit and look as much as work, and banish all cares. I found my grandfather as often just looking as working (and he led about 20 families from his market garden).

Meaning in gardening: there is a very conscious sense of doing a job that is worthwhile, and of direct value to others. Gardening, especially food gardening, is “right livelihood“.

Life interest: perhaps derived from the above.

Every day, every season there is change, something new to observe, and constant learning. Permaculture greatly adds to this interest, and has the dimensions of a life-oriented chess game, involving the elements, energy, and the dimensions of both life-forms and building structures (also with political, social, financial, and global implications).

 

Yield

Here we come to a grave impasse. There is no doubt that the once-off yield of a ploughed and fertilized monoculture, supported by chemicals and large energy inputs, can out-yield that of almost every other production system.

But: at what public cost?, for how long maintained?, with what improvement in nutrition?, with what guarantee of sustainability?, with what effect on world hunger?, on soils?, and on our health?

There is now abundant proof that such forced yields are temporary, and that plough cultures destroy soils and societies.

 

These are some very awkward questions to ask of the agricultural establishment, for very few, if any, modem agricultural systems do not carry the seeds of our own destruction.

These systems are those that reserve public financial support, yet they destroy the countryside in a multitude of ways, from clearing the land of forest, hedgerow, and animal species to long-term soil degradation and poisoning .

We are thus obliged , by entrenched bureaucracies, to pay for the destruction of our world , regard less of the long-term costs to be home by our children and our socities.

 

Life In soil

Soil organisms are a major soil factor, and have myriad perceptible and profound effects on pH. mineral content and availability, soil structure, and erosion.

It is not the purpose of people on earth to reduce all soils to perfectly balanced, well-drained, irrigated, and mulched market gardans, although this is achievable and necessary on the 4% of the earth we need for our food production.

Thus, what I have to say of soils refers to that 4%, with wider implications only for those soils (60% of all agricultural soils) that we have ruined by the plough or polluted by emissions from cars, sprays, radioactives and industry.

 

Our largest job is the restoration of soils and forests for the sake of a healthy earth itself.

It is most definitely not to dear, deforest, or ruin any more land, but first to put in order what we have destroyed, at the same time attending to the modest area that we need for our survival and full nutrition.

Without poorly drained, naturally deficient, leached, acidic or alkaline sites, many of the plant species on earth would disappear. They have evolved in response to just such difficult conditions, and have specialized to occupy less than perfect soil sites.

Colin Tudge (New Scientist ’86) muses on the proportion of the British Isles that could be given back to nature.

He comes down with a very conservative estimate of perhaps 60%.

And at that, without letting go of the misconception that it is agriculture (not individual and market gardening) that will actually provide the future food we eat (a common fallacy).

 

John Jeavons estimates (on the basis of gardens) that we could return perhaps 94% of land to its own purposes. Not that I think that we will get there this next decade, but we can start, and our children can continue the process, and so develop new forests and wilderness to explore.

A reduction of the ecological deserts that we have called agriculture is well overdue, as is a concomitant reduction in the twin disasters of newspapers and packaging derived from ancient forests. 

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